The Rev. Martin Luther King Jr. sent a telegram to Mary Peabody's son, Massachusetts Gov. Endicott Peabody. King thanked the governor for the sacrifices of his mother, Mary, and for her willingness to be jailed for the St. Augustine sit-in.

Fifty years ago, St. Augustine, Fla., was a quiet, palm-fringed resort town with pastel Spanish colonial buildings. There was warm weather, and the white sand beaches off the Atlantic coast lured thousands of tourists every year. There was also a historic part of downtown that had a building often referred to as "The Old Slave Market," with good reason: For several decades, that had been the building's purpose.

Racial tension in St. Augustine had been bubbling. The town lacked public amenities for blacks — much of the area was segregated. And for years, there had been a growing civil rights movement that had been met with increasingly violent resistance from local whites.

Despite that, it was clear black pushback was growing. As Congress debated passing a civil rights act, black leaders wanted to increase the pressure on elected representatives by highlighting racial injustice and violence in various parts of the country.

The Rev. Martin Luther King Jr. and his Southern Christian Leadership Conference put out a call for white students in the North to skip the beach on their spring break and come to Florida to protest segregation. Inviting young white people to push for civil rights would bring attention to places where the national media had ignored dramatic racial injustices.

To further increase the pressure, King's deputy, Hosea Williams, visited Boston to see if any elderly Bostonians would volunteer. Williams believed the image of grandmothers being ushered off to jail would be a sure bet in gaining national publicity for places that had been in the shadows. One of Williams' volunteers turned out to be 72-year-old Mary Parkman Peabody, wife of the former bishop of the Episcopal Diocese of Central New York and mother of Endicott Peabody, then-governor of Massachusetts.

Historian David Colburn, professor emeritus at the University of Florida, said the SCLC knew St. Augustine was preparing to celebrate its 400th birthday, and decided to hijack the tourist message with a civil rights message.

"It was clear that they were trying to mobilize a civil rights army to come to St. Augustine to lead demonstrations against the segregation policies of the community," Colburn says.

The late governor's brother, Samuel Peabody, says his mother had been involved in what she called "justice issues" for several years.

"She never had a doubt about her opinions, and she stood up," says Peabody, a retired New York businessman. "She was articulate about them at all times."

The last week of March 1964, Mary Peabody and a few other powerful women flew down to St. Augustine. With members of the SCLC, they tried to attend services at Trinity Episcopal Church. The rector locked the doors.

They attempted to go to several local restaurants, and were turned away. Then the group decided to try for lunch at the Ponce de Leon Motor Lodge —which just happened to have a group of reporters staying there.

Mary Peabody, says Colburn, was clear about the probable consequences: "She even ran into an old friend on the street in St. Augustine as they were going to the hotel restaurant, and was asked what she was doing there and said, 'Well, I'm about to get arrested!' "

Which was true. She spent two nights in the local jail before her youngest son, Malcolm, was allowed to bail her out. Samuel Peabody says he got word a week later, when he returned from a trip abroad:

"I was not told about it at all. What surprised me was I saw my mother on the front page of every newspaper in the country!" he recalls. "Or at least every newspaper where I was at the time." (Southern newspapers were the exception, for obvious reasons.) The picture of Mary Peabody, with a proper handbag and pearls, her white hair topped by an ever-present hat, made national news.

It was a turning point.

Black St. Augustine residents had been working to break segregation for years before Mary Peabody's arrival, but her presence in March 1964 made their struggles visible. Malcolm Peabody says his mother knew her job wasn't the same as black local protesters, and was aware she played a very specific role:

"She did not face the danger that so many of them did, but the fact that she was able to generate the publicity made her special."

That publicity was a catalyst for other demonstrations soon after, some of them quite violent. The St. Augustine Movement would become known as one of the most critical — and until recently, one of the least-known — campaigns in the civil rights history.

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Transcript

AUDIE CORNISH, HOST:

This year marks the 50th anniversary of several civil rights milestones, including Freedom Summer and the murders of three civil rights workers in Mississippi. It's also the 50th anniversary of the movement to desegregate St. Augustine, Florida. NPR's Karen Grigsby Bates has this story about a critical moment and an unexpected champion in what came to be known as the St. Augustine Movement. A warning: This piece contains images and language some may find upsetting.

KAREN GRIGSBY BATES, BYLINE: Warm weather, white sand beaches, gentle breezes. In 1964, St. Augustine was a quiet, palm-fringed resort town with pastel Spanish colonial buildings and a historic part of downtown that contained a building that was often referred to as the old slave market because, for several decades, that had been its purpose. In an oral history from the St. Augustine Civil Rights Library, Bernice Lacey Harper described the lack of public amenities for black St. Augustinians.

BERNICE LACEY HARPER: The horses had a trough and they could get a cold drink of water. But blacks could not drink from the water fountains.

BATES: For years, there had been a growing civil rights movement that had been met with increasingly violent response. Dr. Robert Hayling, a prominent black dentist with an integrated practice, had been a leader in the struggle. In September 1963, he and two colleagues were run off the road and kidnapped by the Ku Klux Klan. In his oral history, Dr. Hayling described what happened next.

DR. ROBERT HAYLING: Literally, after being beaten severely, we were stacked like cordwood on top of each other. And even in the group, one of the leaders had asked the people assembled if they had ever had the pleasure of smelling a nigger burn.

BATES: Fortunately, they avoided that grisly fate when a sympathetic white man slipped away and made a hasty call to authorities in nearby Jacksonville, who intervened. But it was clear black rejection of segregation was growing. To increase the pressure, Martin Luther King and his Southern Christian Leadership Conference put out a call for white students in the North to skip the beach on their spring break and instead come to Florida to protest segregation. Historian David Colburn, professor emeritus at the University of Florida, said the SCLC knew St. Augustine was preparing to celebrate its 400th birthday with a year's worth of festivities.

DAVID COLBURN: And it was clear that they were trying to mobilize a - their civil rights army to come to St. Augustine to lead demonstrations against the segregation policies of the community.

BATES: One of the volunteers turned out to be Mary Parkman Peabody, the wife of a former Episcopal bishop and the mother of the then-governor of Massachusetts, Endicott Peabody. By birth and by marriage, Mrs. Peabody was connected to two of Boston's most ancient and prominent families. Her son, Samuel Peabody, said she'd been active in what she called justice issues for years, sometimes in the face of stiff disapproval from her elite social circles.

SAMUEL PEABODY: She never had a doubt about her opinions, right, and she stood up. She was quite articulate about them at all times.

BATES: And, says David Colburn, civil rights was already very much on Mrs. Peabody's radar.

COLBURN: She had, through her family, particularly through her husband's association with Martin Luther King, come to supporting the Civil Rights Movement and anxious to see it successful.

BATES: So, 72-year-old Mary Peabody and a few other similarly powerful women flew down to St. Augustine intending to demonstrate but, as a compromise to their worried families, not intending to be jailed. Eventually, though, they decided they had to join the protesters behind bars. We need some old people in this thing, she told reporters as she was led away. We're just what they say we are: do-gooders. Malcolm Peabody bailed his mother out two days later and says the authorities treated her well.

MALCOLM PEABODY: They were all polite to her and particularly polite because she was a lady of 72 years old and dressed properly.

BATES: Just as the SCLC had hoped, the story made national news. Photos accompanying it show an elderly lady with snowy hair and pearls placidly peering between the bars of her cell. Samuel Peabody had been abroad and returned to find his mother was famous, or infamous, depending on your own point of view.

PEABODY: What surprised me was that I saw my mother on the front page of every newspaper in the country.

BATES: Historian David Colburn says it was a turning point.

COLBURN: St. Augustine was one of those critical three or four campaigns that unfolded in the early 1960s that brought about substantive racial change in America.

BATES: Black St. Augustine residents had been working to break segregation for years before Mrs. Peabody's arrival, but her presence in March 1964 made their struggles visible. Son Malcolm Peabody says his mother was pleased she'd contributed to their efforts.

PEABODY: She was tickled that she could be helpful, as indeed she was.

BATES: And the momentum from her St. Augustine visit would become a springboard for even larger demonstrations a few months later. Karen Grigsby Bates, NPR News. Transcript provided by NPR, Copyright NPR.